JPH09272606A - Running controller for stacker crane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide reduction in the cost and size of a device by obtaining a required swing reducing effect without requiring a special device for swing reduction. SOLUTION: This running controller for stacker crane, which makes a running carriage 4 on which a mast 5 for elevating an elevating platform 6 is installed vertically run along guide rails 2, 3 disposed on a floor and a ceiling part, is provided with a distortion detecting means 10 for detecting the distortion of the mast 5 in its running direction and a running control means which conducts running control for the running carriage based on an adding result obtained by adding the running command of the running carriage 4 to a value of which a detection signal of the distortion detecting means 10 is multiplied by a prescribed gain.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a stacker crane traveling control device for reducing swing of a mast that occurs when positioning a stacker crane used in an automatic warehouse or the like.

[0002]

2. Description of the Related Art Stacker cranes used in automated warehouses include a mast that is erected on a traveling carriage, an elevator that moves up and down along the mast, a floor guide rail that guides the traveling carriage, and a crane above the mast. It is configured to have a guide roller provided on the ceiling, a ceiling guide rail for guiding the guide roller, and the like.

In this stacker crane, in recent years,
Although the height and weight of the mast have been increased, the rigidity of the mast relatively decreases with the increase in the weight and weight of the mast, and as a result, the mast swings (remaining (Vibration) increased, which hindered improvement of cycle time.

Therefore, as a conventional technique for solving such a problem, Mitsubishi Heavy Industries Technical Report (VOL.26 NO
6 (1989-11)), "Development of earthquake-proof / vibration-type automatic storage equipment". According to this conventional technique, the guide roller provided on the crane ceiling is always pressed against the guide rail by the spring, and the rotating shaft of the guide roller is connected to the shaft of the viscous damper via the electromagnetic clutch. During traveling, the guide roller is smoothly rotated by releasing the electromagnetic clutch to cut off the viscous resistance of the viscous damper.When the traveling carriage stops traveling, the electromagnetic clutch is connected and the viscous resistance of the viscous damper is guided by the guide roller. The effect of damping the oscillation is obtained by transmitting the information to

[0005]

However, in this prior art, since devices such as viscous dampers and electromagnetic clutches are used to obtain the oscillation damping effect, devices such as viscous dampers and electromagnetic clutches are required. The equipment cost will increase.

In an automated warehouse, racks for storing loads are stored in a very high density in order to store more loads. Therefore, when attaching the devices such as the viscous damper and the electromagnetic clutch to the stacker crane, it is necessary to take care not to interfere with these devices and the rack, and it is desirable that the device be as small as possible. However, as mentioned above,
The damping force required to reduce the swing of the mast tends to increase with the rise of the stacker crane, and therefore the devices such as the viscous damper and the electromagnetic clutch have to be increased in size. As described above, in the above-mentioned conventional technique, when it is attempted to obtain a larger swing reduction effect,
There is a problem when the device configuration for that purpose becomes large and interference with racks of an automated warehouse is taken into consideration.

The present invention has been made in view of the above circumstances, and it is possible to obtain a desired rocking reduction effect without requiring a special device for rocking reduction, and to reduce the cost of the apparatus. It is an object of the present invention to provide a stacking crane travel control device that is downsized and downsized.

[0008]

According to the present invention, a stacker crane travels along a guide rail provided on a floor surface and a ceiling portion of a traveling carriage on which a mast for raising and lowering a lifting platform is erected. In the control device, a strain detecting means for detecting the strain in the traveling direction of the mast, and a value obtained by multiplying the detection signal of the strain detecting means by a predetermined gain are added to the traveling command of the traveling vehicle to obtain the addition result. And a traveling control means for controlling traveling of the traveling vehicle based on the traveling vehicle.

According to this invention, a value obtained by multiplying the distortion signal of the mast by a predetermined gain is added to the travel command for controlling the travel of the travel vehicle, and the travel control of the travel vehicle is performed based on the addition result. The required swing reduction effect is obtained only by software control. That is, instead of performing the swing reduction operation from the time when the traveling is stopped, the traveling control for reducing the swing is performed even during traveling so that the swing of the mast after the traveling is stopped is quickly stopped. ing.

[0010]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 shows an example of the overall structure of a stacker crane to which the present invention is applied.

In FIG. 1, a stacker crane 1 travels along a guide rail 2 laid on the floor and a guide rail 3 arranged on the ceiling.

The stacker crane 1 has a traveling carriage 4 traveling along a guide rail 2, a gate-shaped mast 5, and
It has a lift table 6 that moves up and down along the mast 5. A plurality of guide rollers 7 that roll along the guide rails 3 on the ceiling side are provided above the mast 5. An encoder 8 for detecting the position of the traveling carriage 4 is connected to the wheels 9 of the traveling carriage 4.

A strain sensor 10 is provided below the mast 5, and the strain sensor 10 detects the rocking strain before and after the traveling direction A generated in the lower portion of the mast.

In such a structure, as described above, the mast 5 swings back and forth in the traveling direction during and after the stacker crane 1 is traveling. At this time, the swing mode of the mast 5 is dominated by the first-order mode as shown by the one-dot chain line in FIG. Occurs.

Here, in general, the signal obtained from the strain sensor 10 is apt to carry noise, and therefore S is as much as possible.
It is necessary to mount the strain sensor 10 at a position where strain easily occurs so that the / N ratio can be made high. Therefore, in this case, the strain sensor 10 is attached near the lowermost portion of the mast 5 where the maximum strain occurs. In addition,
Even if the strain sensor 10 is attached near the uppermost portion of the mast 5, it is possible to obtain a strain signal having an S / N ratio almost equal to that when attached to the lowermost portion.

Next, FIG. 2 shows another stacker crane 20.
In this case, the mast 5 is not a gate type as described above but is composed of a single column 21. In FIG. 2, components that achieve the same functions as those of the components in FIG. 1 are designated by the same reference numerals, and duplicate description will be omitted.

Also in the stacker crane 20 of FIG. 2, the swing mode of the mast 5 is dominated by the first-order mode as shown by the one-dot chain line in FIG. 2, and the maximum strain is generated in the lower part of the mast 5. . Therefore, in the case of the stacker crane 20 composed of this one mast, the strain sensor 10 is attached near the lowermost portion of the mast 5. In the case of this one stacker crane 20, the strain is not so large near the top of the mast, so it is better not to attach the strain sensor 10 near the top of the mast 5.

FIG. 3 shows a construction of a traveling control device 30 for controlling traveling of the traveling carriage 4 of the stacker crane 1 or 20 shown in FIG. 1 or 2.

In FIG. 3, the traveling control device 30 transmits the strain signal detected by the strain sensor 10 to the A / D (analog / analog /
A / D converter 31 that performs digital) conversion, a pulse counter 32 that counts pulse signals output from encoder 8, a position command determination unit 33 that generates a position command value for the traveling carriage, and an A / D converter 31 Distortion signal ε, output of pulse counter 32 and position command determination 33
A calculation unit 40 for calculating a travel speed command Vc for travel control based on the position command Xc from the D / A and a D / A for converting the travel speed command Vc output from the calculation unit 40 into a D / A value.
And a converter 41. Travel control device 3
The traveling speed command Vc output from 0 is input to the traveling vehicle drive device 50. The traveling vehicle driving device 50 controls traveling of the traveling vehicle 4 of the stacker crane 1 or 20 according to the input traveling speed command Vc.

FIG. 4 shows the operation of the arithmetic unit 40 having such a configuration.
This will be described with reference to the flowchart of FIG.

First, the calculation unit 40 inputs the position command value Xc from the position command determination unit 33 (step 100), and then inputs the count value of the encoder pulse from the pulse counter 32, and the count value has a predetermined engineering unit. The actual position Xr of the traveling carriage 4 is calculated by multiplying the conversion constant (step 110).

Next, the calculation section 40 inputs the mast swing distortion signal ε via the A / D converter 31 (step 120).

In the calculation section 40, the calculation shown in the following equation (1) is performed based on these three signals Xc, Xr and ε,
Travel speed command value Vc to be output to the D / A converter 41
Is determined (step 130).

Vc = Gp (Xc-Xr) + G1.epsilon.Gp: Position loop gain G1: Gain (1) That is, a normal value obtained by multiplying the deviation between the position command value Xc and the actual value Xr by the position loop gain Gp. To the traveling speed command value Gp (Xc-Xr) for positioning, a value G1 · ε obtained by multiplying the mast swing distortion signal ε by a predetermined gain G1 is added, and this added value is the final traveling speed. The command Vc is used.

The traveling speed command Vc is output to the traveling vehicle drive device 50 via the D / A converter 41 (step 140). Therefore, the traveling vehicle drive device 50 drives the traveling vehicle 4 in accordance with the input traveling speed command Vc.

In the traveling control device 30, the traveling control as described above is repeated until the traveling carriage 4 is completely stopped.

In the above embodiment, depending on the values of the position loop gain Gp and various control parameters of the traveling vehicle drive unit 50, the swinging reduction effect of the mast 5 can be reduced even if the gain G1 in the equation (1) is increased. Is not obtained sufficiently,
On the contrary, it may cause oscillation.

In such a case, the final traveling speed command Vc is calculated by a method using the following arithmetic expression, and the traveling carriage 4 is operated by the calculated traveling speed command Vc.
To control traveling.

Method (i) Vc = Gp (Xc-Xr) + G2 (dε / dt) Gp: Position loop gain G2: Gain (2) That is, according to this method (i), the normal positioning described above is performed. To the running speed command value Gp (Xc-Xr) for adding, the value G2 · (dε / dt) obtained by multiplying the -step differential value dε / dt of the swing distortion signal ε of the mast by a predetermined gain G2 is added. Then, this added value is used as the final traveling speed command Vc.

Method (ii) Vc = Gp (Xc-Xr) + G3∫εdt Gp: Position loop gain G3: Gain (3) That is, according to this method (i), the above-mentioned normal positioning is performed. To the running speed command value Gp (Xc-Xr), add the value G3 · ∫εdt obtained by multiplying the -integral value ∫εdt of the swing distortion signal ε of the mast by a predetermined gain G3, and add this value to the final value. The running speed command Vc is set.

Further, when a sufficient swing reduction effect cannot be obtained by any of the above-mentioned formulas (1) to (3), the following technique (iii) is used to obtain a sufficient swing. To obtain the motion reduction effect.

Method (iii) Vc = Gp (Xc-Xr) + G1'.epsilon + G2 '. (Dε / dt) + G3'.∫εdt Gp: Position loop gain G1': Gain G2 ': Gain G3': Gain ... (4) That is, according to this method (iii), with respect to the traveling speed command value Gp (Xc-Xr) for the normal positioning described above,
A value G1 ′ · ε obtained by multiplying the mast swing distortion signal ε by a predetermined gain G1 ′, and a negative differential value dε of the swing distortion signal ε.
A value G2 '· (dε /
dt) and a value G3 ′ · ∫εdt obtained by multiplying the negative-order integrated value ∫εdt of the swing distortion signal ε of the mast by a predetermined gain G3 ′, and the added value is the final traveling speed command Vc. I am trying to.

As described above, any one of the above equations (1) to (4) is appropriately selected and selected according to the position loop gain Gp and the values of various control parameters of the traveling vehicle drive device 50. If the traveling speed command Vc is calculated based on the equation and the traveling carriage 4 is controlled to travel according to the calculated value Vc, the swing of the mast can be efficiently reduced during traveling and the swing of the mast after stopping can be reduced. It will be possible to stop it immediately.

For example, the swing displacement of the mast shown in FIG. 5 (b) shows the experimental result when the traveling carriage 1 is driven and stopped at the traveling speed shown in FIG. 5 (a). The traveling speed command Vc does not consider the output ε of the strain sensor 10. That is, Vc = Gp (Xc-Xr).

On the other hand, the experimental results shown in FIGS. 5 (c) and 5 (d) show that the above equation (1) including the output ε of the strain sensor 10 is used.
The traveling speed command Vc is determined based on the equation (4).

As is clear from the comparison of these figures,
According to the control of the present invention, it is understood that the swing of the mast can be efficiently reduced not only after the traveling is stopped but also during traveling, and the swing reducing effect after the traveling is significantly different from the conventional one. .

[0038]

As described above, according to the present invention,
The mast distortion signal is added to the travel command to determine the travel speed command, and the swing of the stacker crane is reduced only by the travel control based on this travel speed command. It is possible to efficiently reduce the swing of the mast after stopping, and it is possible to improve the cycle time of work using the stacker crane. (2) Special swing reduction You do n’t need a new device,
It has excellent effects such as greatly contributing to cost reduction and downsizing of the device.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a stacker crane according to the present invention.

FIG. 2 is an overall configuration diagram of another stacker crane.

FIG. 3 is a block diagram showing a configuration example of a traveling control system of the stacker crane according to the present invention.

4 is a flowchart showing a calculation procedure in a calculation unit shown in FIG.

FIG. 5 is a diagram showing a traveling speed pattern and a swing waveform according to a conventional technique and the present invention.

[Explanation of symbols]

 1 ... Stacker crane 2 ... Floor guide rail 3 ... Ceiling guide rail 4 ... Traveling vehicle 5 ... Mast 6 ... Elevating platform 7 ... Guide roller 8 ... Encoder 10 ... Strain sensor 30 ... Travel control device 40 ... Computing unit

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display area B66F 9/07 B66F 9/07

Claims (7)

[Claims] 1. A traveling control device for a stacker crane, comprising: a traveling carriage on which a mast for raising and lowering an elevating table is erected; and a traveling carriage that travels along guide rails arranged on a floor and a ceiling. Distortion detecting means for detecting distortion in the direction, a value obtained by multiplying the detection signal of the distortion detecting means by a predetermined gain, is added to the traveling command of the traveling vehicle, and traveling control of the traveling vehicle is performed based on the addition result. A traveling control device for a stacker crane, comprising: traveling control means for performing the traveling control. 2. A traveling control device for a stacker crane, comprising: a traveling carriage on which a mast for raising and lowering an elevating platform is erected, traveling along guide rails provided on a floor surface and a ceiling portion. Distortion detecting means for detecting distortion in the direction, and a value obtained by multiplying the -step differential value of the detection signal of the distortion detecting means by a predetermined gain, and add to the travel command of the traveling vehicle and travel based on the addition result. A traveling control device for a stacker crane, comprising: traveling control means for controlling traveling of a carriage. 3. A traveling control device for a stacker crane, comprising: a traveling carriage on which a mast for raising and lowering an elevating platform is erected, traveling along guide rails provided on a floor surface and a ceiling portion. Distortion detection means for detecting distortion in the direction, and a value obtained by multiplying the -integral value of the detection signal of the distortion detection means by a predetermined gain is added to the travel command of the traveling vehicle and traveled based on the addition result. A traveling control device for a stacker crane, comprising: traveling control means for controlling traveling of a carriage. 4. A traveling control device for a stacker crane, comprising: a traveling carriage on which a mast for raising and lowering an elevating table is erected; and a traveling carriage that travels along guide rails provided on a floor and a ceiling. Distortion detecting means for detecting distortion in a direction, and obtaining the -derivative value and -integral value of the detection signal of the distortion detecting means, the detection signal, the -derivative value of the detection signal and the -order of the detection signal A value obtained by multiplying the integral value by each predetermined gain value is added, the added value is added to the travel command of the traveling vehicle, and traveling control means for performing traveling control of the traveling vehicle based on the addition result, A stacking crane traveling control device characterized by being provided. 5. The strain detecting means is provided in a lower portion or an upper portion of the mast, and detects a strain in a traveling direction which is generated in the lower portion of the mast or the upper portion of the mast. The traveling control device for a stacker crane according to claim 3 or claim 4. 6. The mast is a gate-type mast, and the strain detecting means is provided at a lower portion or an upper portion of the mast,
The strain for detecting the traveling direction generated in the lower portion of the mast or the upper portion of the mast is detected.
Alternatively, the traveling control device for the stacker crane according to claim 3 or 4. 7. The mast is composed of one column, and the strain detecting means is provided at a lower portion of the mast to detect a strain in a traveling direction generated at an upper portion of the mast. A traveling control device for a stacker crane according to claim 2, 3 or 4.